The present invention relates generally to a vehicle level selector device of a hydropneumatic suspension unit externally of which an automatic level regulator valve is located and particularly to a vehicle level selector device of this type which is improved to hydraulically operate the level regulator valve to selectively lengthen and shorten the suspension unit so that the vehicle driver can operate a vehicle level selector lever with a minimum or slight operating force.
As is well known in the art, a hydropneumatic suspension unit is provided with a vehicle level selector device to selectively raise and lower the vehicle body with respect to the wheels or the road surface to a desired level independently of a load applied to the vehicle body. An ordinary level selector device is operatively connected to a casing of a vehicle level regulator valve located externally of the suspension unit and is operated to move the casing with respect to a valve spool of the level regulator valve to lengthen and shorten the suspension unit when the vehicle driver moves a vehicle level selector lever to select a desired level of the vehicle body.
A conventional level selector device has been constructed such that the casing of the level regulator valve is moved with respect to the valve spool thereof directly and mechanically by the action of the driver through a wire cable and a rod when the driver operates the level selector lever. Thus, the driver has been required to apply a considerably great operating force for operating the level selector level. Furthermore, it has been necessary to make the level selector device strong so that the device withstands the great operating force. Thus, the device has been expensive to manufacture and has required in the vehicle a bulk space to install it therein. As a result, it has been difficult to put the device into practical use.